Writing is a learned craft. In order to learn to write, you must write. Eventually the classes must be set aside; set a daily work schedule and stick to it. That is not to say you should stop taking classes altogether; learning is a lifetime experience. Sooner or later though, you must take the plunge and go at it on your own.
Have a story to tell, one that you like. Then sit down and get busy. Have your work professionally edited: rewrite, edit, rewrite, until you've gotten it as good as it can be. That's all there is to being a writer.
Take a look at my website to see how I accomplish the task of writing about my passion, the people of Viking Greenland.